1. Field of the Invention
The invention relates to an arrangement comprising light-sensitive or X-ray sensitive sensors arranged in a matrix in rows and columns, which sensors produce charges in dependence upon the amount of incident radiation and each have an electrical switch, for each sensor row a switching line via which the switches can be activated so that the charges of the sensors of the activated sensor row are read simultaneously via associated read lines.
2. Description of the Related Art
Such an arrangement is known from the European Patent Specification 0,028,960 which corresponds to U.S. Pat. No. 4,382,187, and from German Patent Application 4,002,431, which corresponds to commonly-owned U.S. patent application Ser. No. 644,713 filed Jan. 23, 1991 having the same inventors as the present application. In these known arrangements the charges stored in the sensors of the matrix upon exposure to light or X-rays are read out successively in a row-by-row fashion. This is effected in such a manner that only one sensor row at a time is activated via the read line associated with this row. The charge from each sensor of this row is then removed via an associated read line, after which it is further processed. The charges of the sensor rows are thus read out in succession.
In medical X-ray diagnostics it is desirable to utilise such methods not only for recording single images but also for recording rapid image sequences up to 60 images per second. The image sequences may then be recorded by means of the sensor matrix in a continuous or in a pulsed exposure mode. For recording each individual image of such an image sequence the sensor matrix should be set to its initial state, i.e. the sensor matrix should be free from any traces of the last recording. This problem occurs in particular with rapid image sequences because the charges of the sensors are not drained completely during the (rapid) read process. As a result, the individual sensor elements will contain residual charges whose magnitude depends on the exposure intensity of the preceding recording. These charges add to those produced in the sensor during a subsequent image. In terms of time this is to be regarded as nothing else than crosstalk of successive images.